Clooney is suing for 3 million euros in damages, La7 said, after the three men allegedly used the actor's name without his knowledge for a clothing collection.

A large crowd of mostly fans was in the corridors as he testified, La7 said.

"He is very handsome -- much better in person than what I expected," said one woman outside the court. "He is so elegant and so well dressed. He had a white shirt on. Very handsome."

Other women outside the court also commented on Clooney's good looks. "He is always handsome," another woman said.

Clooney was shown documents from the defense that apparently had his signature of approval for the clothing line, La7 said.

Clooney said some of the signatures weren't his, and that others were genuine but had been photocopied, the station said.

"I want to explain well," Corriere della Sera quoted Clooney as saying. "There are false signatures and then there are photocopies of the same signature, repeated a 100 times. I want to say (they are) exactly the same signature. We've compared the sheets and they match perfectly.

"My signature is very easy to find on the internet. But if someone wanted to borrow my signature, they should borrow various signatures of mine, not always the same one for a 100 times."

At that point, Clooney turned to the defendants and said, "You've done a good job -- very good."

Clooney also denied knowing any of the defendants, including a woman who claims to have had an affair with the actor and lived in his villa on Lake Como, in northern Italy, La7 reported.

"I've come here because I believe in justice and because people are using my name to exploit, take advantage of other people, not of me," the newspaper quoted him as saying.

In giving the litany of the companies for whom he advertises, he mentioned Martini, the Italian vermouth brand. Clooney has appeared in a number of European TV ads for the company.

Clooney then repeated his famous line, "No Martini, no party," according to Corriere della Sera. The public in the courtroom burst out laughing.